How to customize the appearance of the WaitingGradient style in the WinForms ProgressBarAdv?

//Specifies the ProgressBar style.
this.progressBarAdv1.ProgressStyle = Syncfusion.Windows.Forms.Tools.ProgressBarStyles.WaitingGradient;
//Customizes the waiting to render.
this.progressBarAdv1.CustomWaitingRender = true;
//Enables the waiting gradient.
this.progressBarAdv1.WaitingGradientEnabled = true;
//Customize the ProgressBar appearance.
this.progressBarAdv1.DrawWaitingCustomRender += new Syncfusion.Windows.Forms.Tools.ProgressBarAdvDrawEventHandler(progressBarAdv1_DrawWaitingCustomRender);
//Handles this event to draw a custom waiting to render.
void progressBarAdv1_DrawWaitingCustomRender(object sender, Syncfusion.Windows.Forms.Tools.ProgressBarAdvDrawEventArgs e)
{
    Region region = new System.Drawing.Region();
    region.MakeEmpty();
    region.Union(e.Rectangle);
    LinearGradientBrush brush = new LinearGradientBrush( new Point(e.Rectangle.X, 0),
            new Point(e.Rectangle.X + e.Rectangle.Width, 0), Color.Blue, Color.Red);
    e.Graphics.FillRegion(brush, region);
    e.Handled = true;
}

' Specifies the ProgressBar style
Me.progressBarAdv1.ProgressStyle = Syncfusion.Windows.Forms.Tools.ProgressBarStyles.WaitingGradient
'Customizes the waiting to render.
Me.progressBarAdv1.CustomWaitingRender = True
'Enables the waiting gradient.
Me.progressBarAdv1.WaitingGradientEnabled = True
'Customizes the ProgressBar appearance.
AddHandler progressBarAdv1.DrawWaitingCustomRender, AddressOf progressBarAdv1_DrawWaitingCustomRender
'Handles this event to draw a custom waiting to render.
Private Sub progressBarAdv1_DrawWaitingCustomRender(ByVal sender As Object, ByVal e As Syncfusion.Windows.Forms.Tools.ProgressBarAdvDrawEventArgs)
    Dim region As Region = New System.Drawing.Region()
    region.MakeEmpty()
    region.Union(e.Rectangle)
    Dim brush As New LinearGradientBrush(New Point(e.Rectangle.X, 0), New Point(e.Rectangle.X + e.Rectangle.Width, 0), Color.Blue, Color.Red)
    e.Graphics.FillRegion(brush, region)
    e.Handled = True
End Sub